Artificial dentures



A. H. SHOVERS ARTIFICIAL DEN May 2, 1967 TUBES Filed July 1, 1963INVENTOR. AARON H. SHOVERS BY FULWIDER PATTON RIEBER LEE,& UTECHTATTORNEYS United States Patent 3,316,639 ARTIFICIAL DENTURES Aaron H.Shavers, 4624 Goidfield Ave., Long Beach, Calif. 90807 Filed July 1,1963, Ser. No. 291,977 Claims. (Cl. 32-2) ticulation.

The occlusal form of the artificial posterior teeth of the presentinvention primarily provides a single stroke grinding action with nolateral excursion in centric position. This is based upon the conceptthat human mastication is primarily a substantially direct closingmovement of the mandible, occlusal contact first occurring between themandibular buccal cusp tips and the buccal 0r lingual edges of themaxillary fossa on the working side of the mouth. Thereafter, themandibular buccal cusps are guided by the buccal and lingual slopes ofthe maxillary fossa, such guidance continuing until the mandible hasmoved completely vertically into centric, in a combined cutting andgrinding action.

Heretofore, prior types of artificial posterior teeth have been formedto permit relatively large mandibular excursions by designing them tomatch the condylar inclination or by completely eliminating cuspalinterference by eliminating cusps. For example, in one prior art type,all portions of the cusp formation which might possibly interfere withrelatively free lateral mandible excursions are removed, and in anotherprior art design the occlusal surfaces are substantially devoid of anycusps, the occlusal surface angles being comparatively low and shallowto enable the mandibular teeth to protrusively and laterally slide, bothin and out of centric. As a consequence, the wearer was effectivelydenied any clue as to the location of his true centric, and experienceddiscomfort in mastication and difiiculty in maintaining his dentures inproper position, with concurrent mandibular class three type protrusion.

Other prior types of teeth were designed with occlusion of both buccaland lingual cusps to. allow completely free lateral and protrusivemandibular movements in and from centric occlusion by means of a complexsystem of balancing the cusp angles to the condyles of the human jaw.

Accordingly, it is an object of the present invention to provideartificial posterior teeth having a type of cusp interdigitation and nolateral or protrusive excursion in centric, and in which only themandibular buccal cusps are guided into centric by the sloping surfacesof the maxillary fossa. It is an important aspect of the inven tion thatthe engagement between the maxillary and mandibular teeth in centricposition is limited to the apices of the mandibular buccal cusps, themaxillary fossa within which they are received being of the same radiusat the apex and then flaring out to a greater radius than the radius ofcurvature of the cusps received to permit some protrusion and lateralexcursion when the mandibular teeth are just out of engagement with themaxillary teeth. In this regard, the radius of curvature of each suchfossa is preferably larger for an ovoid mouth, compared to a taperedmouth, and preferably still larger for the square mouth, recognizingthat a square and ovoid type person will require more lateral andprotrusive movement.

Another object of the present invention is to provide a pair ofcooperating dentures in which all the posterior maxillary teeth areconstructed as a single unit for each side of the month including fossaein the form of troughs 3,316,639 Patented May 2, 1967 arranged in aV-configuration, substantially in alignment with the bony ridges, sothat the fossae of the posterior teeth on either side of the mouthdefine forwardly convergent troughs. Similarly, the mandibular teeth oneach side of the month have buccal cusps substantially parallel to thebony ridges for receipt within the maxillary fossae whereby protrusiveor forward mandibular movement is substantially prevented byinterengagement of the cooperating occlusal formations of the maxillaryand mandibular teeth when the dentures are in centric.

A further object of the invention is to provide artificial posteriormaxillary and mandibular teeth characterized by minimum contact, therebeing no mandibular lingual cusps, whereby total mastication pressuresare comparatively low and the amount of bony resorption iscorrespondingly reduced. However, the limited contact area is alsoproductive of high cutting pressures with relatively small closingforces.

A further object of the present invention is to provide artificialposterior teeth of the aforementioned character which providecomparatively close cusp interdigitation to substantially preventlateral and protrusive relationships in centric position, permittingsuch relationships only upon slight separation of the maxillary andmandibular teeth. Thus, actual engagement between the teeth during acutting operation occurs only in the centric position.

Yet another object of the present invention is to provide artificialposterior teeth of the aforementioned character which are adapted tointerengage only in centric to thereby properly seat the mandibulardenture upon the bony ridge and maintain it in place.

Another object of the invention is to provide artificial posterior teethcharacterized by an occlusal formation having surfaces which define amandibular lingual food table and which are closely positioned incentric to provide some grinding, masticating action, but which neveractually engage. Thus the tongue and checks may guide food into placeupon this lingual food table just prior to the closure of the teeth.Labial and lingual protection during mastication is afforded by generousor heavy contours adjacent the food table, which guide the cheek andtongue out of interfering relationship during movement of the teeth intocentric to prevent their being bitten. These same contours are designedto stimulate the proprioceptive nerves involved in human mastication toassure proper function.

Other objects and features of the invention will become apparent fromconsideration of the following description taken in connection with theaccompanying drawings, in which:

FIG. 1 is a plan view of a portion of a denture, illustrating theocclusal surfaces of artificial posterior maxillary teeth embodying thepresent invention;

FIG. 2 is a plan view of a portion of a denture, illustrating theocclusal surfaces of artificial posterior mandibular teeth embodying thepresent invention;

FIG. 3 is an enlarged, elevational view of the buccal sides of theposterior maxillary and mandibular teeth of FIGS. 1 and 2 in cooperatingrelationship, the teeth being those on the right side of the mouth;

FIG. 4 is an enlarged, elevational view of the lingual sides of theteeth of FIG. 3;

FIG. 5 is an enlarged, detail view taken along the line 55 of FIG. 3;and

FIG. 6 is a view identical to FIG. 5, but illustrating the teeth inengagement in centric relationship.

Referring now to the drawings, and particularly to FIG. 1 thereof, aportion of an upper or maxillary plate or denture 10 is illustratedwhich mounts four artificial posterior teeth 12, as a single unit, onone side thereof, and four artificial posterior teeth 14, as a singleunit, on

the other side, each set of the four teeth 12 and 14 including a pair ofmolars and a pair of bicuspids. Similarly, in FIG. 2 there isillustrated a portion of a lower or manibular plate or denture 16 whichmounts four artificial posterior teeth 18 on one side thereof and fourposterior teeth 20 on the other side, each set of the teeth 18 and 20including a pair of molars and a pair of bicuspids.

Although the drawings illustrate the case in which full upper and lowerreplacement of the posterior teeth is made, it is to be understood thatthe scope of the present invention encompasses utilization of as few asa pair of cooperating maxillary and mandibular teeth, whereby theinvention is adapted for use in stationary partial dentures or bridgesas well as in completely removable dentures.

The right-hand posterior teeth 14 and 20 are illustrated in FIGS. 3 and4 with their occlusal surfaces in cooperating or complementaryrelationship in centric position, the comparatively close cuspinterdigitation in this centric position preventing appreciablemandibular lateral excursion, as will be more particularly describedhereinafter.

As best illustrated in FIGS. and 6, each maxillary posterior tooth 14,whether it be molar or bicuspid, has its occlusal surfaces formed intoan elongated buccal cusp 22, an elongated lingual cusp 24, and anintermediately located elongated fossa 26. The cusps 22 and 24 and fossa26 are elongated in a posterior-anterior direction, substantiallyparallel to the bony ridges of the mouth.

The buccal cusp 22 is characterized by a rounded apex 28, and a buccalcontour 30 having a relatively large or generous radius of curvature tolocate the cheek of the wearer well out of interfering engagement withthe occlusal surfaces of the teeth 14 and 20.

The fossa 26 is characterized by a gradually and smoothly sloping buccalsurface 32 and a smoothly sloping lingual surface 34, the base ordeepest portion 36 between the surfaces 32 and 34 having a radius ofcurvature which is sufiiciently small to limit its arc of contact withthe mandibular tooth 20 to approximately 23 millimeters, as will be moreparticularly described hereinafter.

The lingual cusp 24 is characterized by a lingual contour having anupper portion 38 which is slightly convex, and a lower portion 40 whichis almost flat, sloping gradually inwardly and downwardly until itintersects the lingual surface 34 of the fossa 26. As will be seen, thelingual surface 40 is never in engagement with the opposing orcomplementary surface of the mandibular tooth 20, always being spacedtherefrom approximately one-half millimeter. This desirably reduces thearea of engagement between the teeth 14 and 20 to thereby reduce theforces necessary to produce satisfactorily high cutting pressures, whileyet maintaining overall mastication pressures at a comparatively lowlevel.

Although the artificial teeth of the present invention may be made ofany suitable material, the maxillary teeth 12 and 14 are preferablyconstructed in gold and provided with a porcelain overlay 42 forcosmetic purposes, as best illustrated in FIG. 5.

The mandibular tooth 20 is provided with occlusal surfaces which arecomplementary to the occlusal surfaces just described in connection withthe maxillary tooth 14, such mandibular surfaces being constituted by anelongated buccal cusp 44, an elongated lingual lip 46, and anintermediately located food table 56.

The buccal cusp 44 is provided with a buccal contour 50 which slopesslightly inwardly from the vertical, while the apex of the buccal cusp44 is characterized when viewed or projected upon a buccal-lingualplane, by a circularly curved or rounded surface having a radius ofcurvature identical to the radius of curvature of the maxillary fossa 26and then sloping down to a slightly smaller radius of curvature. Incentric position, these apical radii of curvature provide abuccal-lingual arc of contact 52 which is preferably approximately 2millimeters for a tapered type of mouth, 2 /2 millimeters for an ovoidtype of mouth, and 3 millimeters for a square type of mouth, thuspermitting slightly more generous lateral accommodation for mandibularseating for the square type of mouth, for example. However, it isimportant to note that when the teeth 14 and 20 are in centric position,there is no lateral excusion and the fossa 26 cannot rock to any extentabout the round apex of the buccal cusp 44 since there is centricbalancing on the other side of the mouth.

The lingual lip 46 is characterized by a lingual contour 54 having agenerous convex contour to suitably space the tongue away frominterfering engagement with the occlusal surfaces of the teeth 14 and20. In this regard, the lingual and buccal contours 54 and 30 serve alike purpose in properly orienting the tongue and cheek of the wearer ofthe dentures 10 and 16.

The inner or buccal slope of the linqual ridge or lip 46 ischaracterized by an inwardly and downwardly sloping, slightly concavesurface which gradually approaches the horizontal plane to define a foodtable 56 for receiving food placed thereon by the tongue. The lip 46tends to retain the food upon the table 56 during mastication thereofbetween the confronting or opposing surfaces 40 and 56, it being againnoted that the surfaces 40 and 56 are at all times spaced apart so thatactual contact does not take place, even during mastication. This isbest shown in FIG. 6 wherein such surfaces are illustrated as beingspaced apart, occlusal contact being limited to the maxillary fossa base36 and the apex of the buccal cusp 44.

In the construction of the teeth 14 and 20, the maxillary fossa base 36is preferably located along the longitudinal center line of the tooth14, and the apex of the mandibular buccal cusp 44 located as close tothe center line of the tooth 20 as possible. This develops balancedforces upon the bony ridges of the mouth, particularly of the mandible,since the forces developed upon mastication will then act substantiallyvertically. This reduces any tendency of the mandibular denture towobble or tip when the teeth on one side of the denture are engaging orcrushing food without corresponding crushing of food on the oppositeside of the denture.

As best viewed in FIGS. 2 and 3, the posterior and anterior occlusalsurfaces of the teeth 20 are preferably rounded to provide escapepassages or sluiceways 58 therebetween to permit masticated food toescape from between the teeth during mastication. In addition centralsluiceways 60 are provided on the buccal sides of the molars. Thisprevents the development of excessive pressures between the opposedteeth and otherwise facilitates efficient mastication of food, as iswell known.

Referring again to FIGS. 1 and 2, the V-shaped or anteriorly convergentorientation of the maxillary fossa 26 of all of the posterior teeth, andof the mandibular buccal cusps 44 received therein, provide aninterlocking and wedging which prevents any lateral or protrusiveexcursion of the mandible when the teeth are in centric. The slopingsurfaces of the maxillary fossa 26 guide the mandibular cusps 44 intothe centric position and afford the wearer with a positive indication ofthe location of his centric position. This promotes a more naturalmastication action, and eliminates any need for the prior art practiceof balancing artificial teeth to function in extreme lateral andprotrusive relationship. This greatly simplifies the manufacture andfitting of artificial teeth, as Will be apparent to those skilled in theart.

It is important to note that the combined wedging action and occlusalcontact between the maxillary and mandibulary teeth occurs only in thecentric position upon mandible closure. This substantially prevents thedentures from becoming dislodged during mastication since themastication pressures occur only in the centric position and in thatposition are precisely directed so as to firmly and accurately seat thedentures upon their adjacent bony ridges.

Thus, artificial posterior teeth have been provided according to thepresent invention which are adapted to effect occlusal contact betweenthe maxillary and mandibular teeth in centric position only, and inwhich such contact is limited to the apices of the mandibular buccalcusps. It is another salient feature of the invention that the maxillaryfossae within which such buccal cusps are received have the same apicalradii of curvature and then flare out to a greater radius of curvaturethan the cusps to thereby permit slight mandibulary protrusive andlateral excursion only when the mandibular teeth are just out ofengagement. In addition, the mandibular buccal cusps and the maxillaryfossa are longitudinally oriented in substantially parallel relationshipwith the bony ridges of the mouth, somewhat in a V configuration whichis protrusively or anteriorily convergent whereby protrusive mandibularmovement in centric position is substantially prevented.

Various modifications and changes may be made with regard to theforegoing detailed description without departing from the spirit of theinvention or the scope of the following claims.

I claim:

I. In a denture, artificial maxillary and mandibular posterior teeth,each maxillary tooth having a fossa defining a buccal cusp and a lingualcusp, and each mandibular tooth having a food table and a buccal cusp,said mandibular food table being arranged to move into confrontingrelationship with said lingual cusp and said buccal cusp being arrangedto cooperate with said maxillary fossa, the occlusal contact betweensaid maxillary and said mandibular teeth being limited to the apex ofsaid buccal cusp and the base of said maxillary fossa.

2. In a denture, artificial maxillary and mandibular posterior teeth,each maxillary tooth having an elongated anterior-posteror fossadefining an elongated buccal cusp and an elongated lingual cusp, andeach mandibular tooth having a substantially flat food table and anelongated buccal cusp, said mandibular food table being arranged to moveinto confronting relationship with said lingual cusp and said buccalcusp being arranged to cooperate with said maxillary fossa, the occlusalcontact between said maxillary and said mandibular teeth being limitedto the apex of said buccal cusp and the base of said maxillary fossa.

3. In a denture, artificial maxillary and mandibular posterior teeth,each maxillary tooth having an elongated, substantially centrallylocated anterior-posterior fossa defining elongated lingual and buccalcusps, and each mandibular tooth having a substantially flat food tabledefining an elongated lingual lip and an elongated buccal cusp, saidmandibular food table being arranged to move into confrontingrelationship with said maxillary lingual cusp, and said mandibularbuccal cusp being arranged to engage said maxillary fossa and preventocclusal contact between said maxillary lingual cusp and said foodtable, occlusal contact being limited to the apex portion of saidmandibular buccal cusp and the base of said maxillary fossa.

4. In a denture artificial maxillary and mandibular posterior teeth,each maxillary tooth having an elongated, substantially centrallylocated anterior-posterior fossa defining elongated lingual and buccalcusps, and each mandibular tooth having a substantially fiat food tabledefining an elongated lingual lip and an elongated buccal cusp, saidmandibular food table being arranged to move int-o confrontingrelationship with said maxillary lingual cusp, and said mandibularbuccal cusp being arranged to engage said maxillary fossa and preventocclusal contact between said maxillary lingual cusp and said foodtable, occlusal contact being limited to the apex portion of saidmandibular buccal cusp and the base of said maxillary fossa, said apexportion being arcuate in buccal-lingual cross section and adapted forsaid occlusal contact over approximately 2-3 millimeters thereof.

5. In a denture, artificial maxillary and mandibular posterior teeth,each maxillary tooth having an elongated, substantially centrallylocated anterior-posterior fossa defining elongated lingual and buccalcusps, and each mandibular tooth having a substantilly flat food tabledefining an elongated lingual lip and an elongated buccal cusp, saidmandibular food table being arranged to move into confrontingrelationship with said maxillary lingual cusp, and said mandibularbuccal cusp being arranged to engage said maxillary fossa and preventocclusal contact between said maxillary lingual cusp and said foodtable, occlusal contact being limited to the apex portion of saidmandibular buccal cusp and the base of said maxillary fossa, said apexportion being arcuate in buccal-lingual cross section and characterizedby a radius of curvature the same as that of the mating said base ofsaid maxillary fossa.

6. A pair of cooperating dentures including, respectively, maxillaryposterior teeth and mandibular posterior teeth, said maxillary teetheach having an elongated, substantially posteriorly-anteriorly alignedfossa defining a buccal cusp and a lingual cusp, said fossae on oppositesides of the maxillary denture extending in anteriorly convergentrelationship, and said mandibular teeth having elongated buccal cuspsadapted to be received within said fossae in centric position tosubstantially prevent protrusive mandibular excursion, said maxillaryand mandibular teeth also including complemental occlusal surfacesdefining a food table area wherein food is crushed during mandibularclosure, said teeth being constructed and arranged to always orient saidsurfaces of said food table area out of occlusal contact.

7. A pair of cooperating dentures including, respectively, maxillaryposterior teeth and mandibular posterior teeth, said maxillary teetheach having an elongated, substantially posteriorly-anteriorly alignedfossa defining a buccal cusp and a lingual cusp, said fass-ae onopposite sides of the maxillary denture extending in anteriorlyconvergent relationship, and said mandibular teeth having elongatedbuccal cusps adapted to be received within said fossae in centricposition to substantially prevent protrusive mandibular excursion, saidmaxillary and mandibular teeth being constructed and arranged to limitocclusal contact therebetween to the bases of said fossae and the apicesof said buccal cusps.

8. A pair of cooperating dentures including, respectively, maxillaryposterior teeth and mandibular posterior teeth, said maxillary teethhaving elongated, substantially posteriorly-anteriorly aligned fossae,said fossae on opposite sides of the maxillary denture extending inanteriorly convergent relationship, and said mandibular teeth havingelongated buccal cusps adapted to be received within said fossae incentric position to substantially prevent protrusive mandibularexcursion, said fossae and said buccal cusps being complementallycurved, the apical radius of curvature of each fossa being substantiallyidentical to that of the mating buccal cusp, the occlusal contactbetween said maxillary and said mandibular teeth being limited to theapices of said buccal cusps and the bases of said maxillary fossae.

9. A pair of cooperating dentures including, respectively, maxillaryposterior teeth and mandibular posterior teeth, said maxillary teetheach having an elongated, substantially posteriorly-anteriorly alignedfossa defining a buccal cusp and a lingual cusp, said fossae on oppositesides of the maxillary denture extending in anteriorly convergentrelationship, and said mandibular teeth having elongated buccal cuspsadapted to be received within said fossae in centric position tosubstantially prevent protrusive mandibular excursion, said maxillaryand mandibular teeth also including complemental occlusal surfacesdefiining a food table area wherein food is crushed during mandibularclosure, said teeth being constructed and arranged to always orient saidsurfaces of said food table area out of occlusal contact, the anteriorand posterior corners of said mandibular teeth, and the centers of themolar buccal cusps, being rounded to provide escape passages from saidfood table area in said centric position.

10. A pair of cooperating dentures including, respectively, maxillaryposterior teeth and mandibular posterior teeth, said maxillary teetheach having an elongated substantially posteriorly-anteriorly alignedfossa defining a buccal cusp and a lingual cusp, said fossae on oppositesides of maxillary denture extending in anteriorly convergentrelationship, and said mandibular teeth having elongated buocal cuspsadapted to be received within said fossae in centric position tosubstantially prevent protrusive mandibular excursion, said maxillaryand mandibular teeth also including complemental occlusal surfacesdefining a food table area wherein food is crushed during mandibularclosure, said teeth being constructed and ar- 5 from said food tablearea.

References Cited by the Examiner UNITED STATES PATENTS 10 2,375,5095/1945 Wiechert 328 2,617,192 11/1952 Goddard 32-2 3,252,220 5/1966Goddard 32-2 RICHARD A. GAUDET, Primary Examiner.

15 ROBERT E. MORGAN, Examiner.

1. IN A DENTURE, ARTIFICIAL MAXILLARY AND MANDIBULAR POSTERIOR TEETH,EACH MAXILLARY TOOTH HAVING A FOSSA DEFINING A BUCCAL CUSP AND A LINGUALCUSP, AND EACH MANDIBULAR TOOTH HAVING A FOOD TABLE AND A BUCCAL CUSP,SAID MANDIBULAR FOOD TABLE BEING ARRANGED TO MOVE INTO CONFRONTINGRELATIONSHIP WITH SAID LINGUAL CUSP AND SAID BUCCAL CUSP BEING ARRANGEDTO COOPERATE WITH SAID MAXILLARY FOSSA, THE OCCLUSAL CONTACT BETWEENSAID MAXILLARY AND SAID MANDIBULAR TEETH BEING LIMITED TO THE APEX OFSAID BUCCAL CUSP AND THE BASE OF SAID MAXILLARY FOSSA.